The fibro-osseous pulleys of the digital flexor mechanism may be adversely affected by trauma or disease, resulting in "bow-stringing" of the tendon, loss of digital flexion, and poor joint motion. Replacement of these pulleys with biological or synthetic materials would be clinically useful to the surgeon (1) when the pulley is traumatically absent, (2) at surgical tendolysis when the pulley is also incorporated in the fibrous adhesions, and (3) at tendon grafting when the pulley is incorporated in the fibrous adhesions. Reconstruction of pulleys with biological materials (i.e. fascia lata, etc.) prevents the immediate mobilization of the digit, since the pulley must "heal" to the bone. Previously recommended synthetic materials (dacron, silastic) do not have biomechanical propeties which are adequate in the replacement of pulleys in the human hand. Replacement pulleys should be technically easy to place, be compatible with surrounding tissues to minimize scar formation, and have immediate maximum strength so that mobilization of the digit can be instituted in the immediate postopertive period. We intend to develop and properly evaluate a synthetic pulley in the human primate, which has anatomical characteristics similar to the human. We are proposing a relatively long term study in the monkey to evaluate a replacement pulley made of woven monofilament nylon (Nitex) as compared to a replacement pulley made of biological materials. The pulleys will be evaluated with respect to (1) the limitation to tendon gliding by restrictive adhesions, (2) the functional competency of the replacement pulley, (3) the integrity of the flexor mechanism structures (pulley, tendon, bone), and (4) the biomechanical properties.